Workers at eight airports in Germany have gone on strike to demand better pay, leaving hundreds of thousands of travelers stranded.
Germany's biggest carrier Lufthansa canceled more than 1,300 flights at its two busiest hubs, Frankfurt and Munich, on Friday after the Verdi trade union called for a full-day strike.
The other affected airports are in the cities of Bremen, Dortmund, Hamburg, Hanover, Leipzig and Stuttgart.
Verdi said it expected the action to have "a strong impact, especially on domestic air traffic, ranging from delays to cancellations and even a partial shutdown of air traffic".
German airport association ADV said the strike would affect around 295,000 passengers and more than 2,300 flights all together.
The strike comes amid similar back-to-back industrial action across Europe which is grappling with a dramatic fall in living standards triggered by high energy prices.
Public sector workers, airport ground crew and aviation security staff are demanding better pay at a time when workers are seeing their incomes eroded by the higher cost of living.
Frankfurt and Hamburg airports urged passengers not to come to the airport at all. Those travelling within Germany were advised to switch to train journeys. Munich airport scrapped all its regular passenger flights.
The strike caps a chaotic week for air travel in Germany. On Thursday, the websites of several German airports had their services disrupted by a suspected cyber attack, a day after a major IT failure at Lufthansa left thousands of passengers stranded.
Dusseldorf, Nuremberg, and Erfurt-Weimar were also among the airports affected by cyber attacks. The websites were either not reachable or flagged up failure messages.
“Once again, airports fell victim to large-scale DDoS attacks,” Ralph Beisel, chief executive of the ADV airport association, said in a statement.
A DDoS or denial-of-service attack involves diverting high volumes of internet traffic to targeted servers by “hacktivists” to knock them offline.
On Wednesday, there was travel chaos at Frankfurt Airport after cable damage at a construction site caused a computer system failure, with more than 200 flights canceled.
German news outlet Der Spiegel said a group of Russian hackers had claimed responsibility for the attack.